The present invention relates to a pipe coupling for streaming various fluids.
A conventional pipe coupling comprises a socket and a plug which can be detachably connected by lock balls, and a sleeve which is axially slidable on the outer circumference of the socket. In this case, in a plugged-in state where the socket and a plug are connected with each other, the sleeve is at a forward-shifted position and prevents the lock balls from moving radially outwardly to lock the plug. To disconnect the plug in locked state, the sleeve is pulled backward so that the lock balls are released.
In this conventional pipe coupling using a slidable sleeve, unintended disconnection of the plug must be securely prevented.
Also, there may arise a problem that the pipe coupling cannot be utilized at a place where it is difficult or impossible to slide the sleeve in the (backward) direction due to limitations of installation space and work space.
Therefore, it is an object of the present invention to provide a pipe coupling which securely prevents unexpected disconnection of the plug and which has excellent operability even though installation space or work space is limited.
According to the present invention, there is provided a pipe coupling including a socket and a plug which respectively have front end portions which can be engaged with each other, and rear end portions connected with pipes. The socket comprises a socket body having an open end where an axial bore for receiving the plug is opened, at least one lock ball which can be moved between a lock position where the lock ball partially projects into the axial bore and an unlock position where the lock ball is retracted thereby making the plug movable in the axial-direction, and a sleeve slidably mounted on the socket body and capable of holding the lock ball at the lock position. The plug has a groove with which the lock ball can be engaged. The socket body has a front end portion close to the open end, and a lock ball engage hole which is formed at the front end portion, contains the lock ball movably in an axial direction and a radial direction, can be retracted from the lock position where the lock ball partially projects into the axial bore, and is elongated in the axial direction. The sleeve is mounted on the outer circumference of the socket body to be rotatable about an axis thereof, and has an inner circumferential surface, a press portion which is formed on the inner circumferential surface and presses the lock ball located at a position close to the open end in the lock ball engage hole toward the lock position, a press release recessed portion capable of retracting the lock ball to the unlock position, and a large diameter portion arranged axially adjacent to the press portion and the press release recessed portion and capable of retracting the lock ball located at a position distant from the open end to the unlock position. The pipe coupling further comprises a sleeve rotation restricting mechanism for restricting a rotation of the sleeve to an angular range between a press position where the press portion opposes the lock ball and a press release position where the press release recessed portion opposes to the lock ball, a collar movably contained in the large diameter portion, and a spring for urging the sleeve toward the press position and for urging the collar toward the open end.
According to the pipe coupling described above, the plug can be engaged in the socket only by inserting the plug into the axial bore from the open end of the socket body. Further, the plug can be separated from the socket only by rotating the sleeve on the socket body about the axis thereof. Accordingly, the sleeve can be operated even in a very narrow space for making easy disconnection. Further, even if an impact force in the axial direction acts on the sleeve, the fitting engagement between the plug and the socket is securely maintained, and the plug is not unexpectedly separated from the socket.
Preferably, the sleeve rotation restricting mechanism has a rotation restricting recessed portion circumferentially extended on one of the outer circumference of the socket body and the inner circumferential surface of the sleeve, and a rotation restricting projecting portion formed on another one, having a length shorter in a circumferential direction than the rotation restricting recessed portion, and projecting into the rotation restricting recessed portion.
Also preferably, the collar and the sleeve have at least one groove formed in one of the collar and the sleeve, as well as a projection formed on the other of the collar and the sleeve, the projection being slidable in the groove only in the axial direction, and the spring is contained in the large diameter portion and has a coil-like shape having an end engaged on the socket body and another end engaged on the collar.
According to a preferred embodiment of the pipe coupling, the pipe coupling further comprises a plurality of projecting portions provided on one of the socket body and the sleeve, and a plurality of recessed portions provided on the other of the socket body and the sleeve and capable of receiving the projecting portions along the axial direction, wherein relative rotation between the socket body and the sleeve is prevented when the plurality of projecting portions are engaged with the plurality of recessed portions, and the relative rotation is allowed when the plurality of projecting portions are contained in a circumferential recessed portion.
In this pipe coupling, to separate the plug from the socket, the sleeve is pulled toward the rear end in a first step, so that the plurality of projecting portions are released from engagement with the plurality of recessed portions and are positioned in the circumferential recessed portion. Thereafter, in a second step, the plurality of projecting portions are guided in the circumferential recessed portion, thereby enabling rotation of the sleeve. Accordingly, only when the movements in two different directions are combined, the plug can be separated from the socket, so that the reliability of engagement is increased and the safety thereof is also improved.
According to another preferred embodiment of the pipe couple, the pipe coupling further comprises a protection cylinder which covers the sleeve and is rotatable, wherein the protection cylinder has a cylindrical wall which is made of a flexible material and creates a clearance from the outer circumferential surface of the sleeve, and rotation of the protection cylinder can be transmitted to the sleeve as an operator press the cylindrical wall into contact with the sleeve.
In case of this pipe coupling, as long as the operator does not press or operate the protection cylinder, the sleeve cannot rotate. Therefore, unexpected disconnection of the plug is prevented securely so that the safety is more improved.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.